/Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/ClusterUnionManager.h
An extension to FindClusterUnionIndexFromParticle to check whether or not the given particle is the cluster union particle itself.
bool IsClusterUnionParticle ( [FPBDRigidClusteredParticleHandle](API\Runtime\Chaos\Chaos\FPBDRigidClusteredParticleHandle) * Particle )